Tübingen and international researchers investigate ice flow speed in northern Greenland, correcting models predicting sea level change
Ice is a material that can flow like a very viscous liquid. In the polar ice sheets, it flows towards the oceans under its own weight. Knowing how fast the ice flows is of crucial importance to predict future sea level rises, particularly under changing climate conditions.
Professors Paul Bons and Ilka Weikusat from the University of Tübingen’s Geosciences Department, working with scientists from the Alfred Wegener Institute in Bremerhaven, the University of Otago (New Zealand) and the Autonomous University of Barcelona (Spain), measured flow velocities at the surface of the northern Greenland Ice Sheet for a new study now published in Geophysical Research Letters. Their analysis of satellite images suggests that the polar ice is softer than scientists believed until now.
The flow has two components: the internal shearing flow that depends on the viscosity of the ice, and basal motion, which is the ice sheet sliding along the bedrock, especially when the ice melts at that base. The satellite images revealed the surface velocities of the ice, which the researchers used to calculate the stresses that drive the flow.
Previous studies indicated that up to 50 percent of the Greenland Ice Sheet is melting at its base. “This new study shows that that is probably overestimated, because previous studies assumed ice to be harder than it actually is,” says Paul Bons. The new assessment significantly reduces the area where basal motion – and therefore basal melting can be expected in the Greenland study area.
“This does not necessarily mean that ice will now enter the oceans more slowly and delay sea-level rise. Instead, the results suggest that the internal deformation of ice is more important than was thought before,” Ilka Weikusat explains. The new findings will be used to adapt the models predicting sea level changes.
The share of ice transport towards the oceans between melting at the base or internal shearing of the whole ice body has to be reconsidered, but cannot be determined from surface data alone. Instead, deep drill cores into fast flowing ice are important, such as the ongoing EastGRIP project in which some of the authors are involved.
Bons, P.D., Kleiner, T., Llorens, M.G., Prior, D.J., Sachau, T., Weikusat, I. Jansen, D.
Greenland Ice Sheet – Higher non linearity of ice flow significantly reduces estimated basal motion. Geophysical Research Letters. First published: 19 June 2018. Doi:10.1029/2018GL078356
Professor Dr. Paul D. Bons
University of Tübingen – Faculty of Science
Geosciences – Structural Geology
Phone +49 7071 29-76469
Junior Professor Dr. Ilka Weikusat
University of Tübingen – Faculty of Science – Geosciences – Glaciology
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung
Phone +49 471 4831 1968
Dr. Karl Guido Rijkhoek | idw - Informationsdienst Wissenschaft
Welcome Committee for Comets
19.07.2019 | Technische Universität Braunschweig
Sea level rise: West Antarctic ice collapse may be prevented by snowing ocean water onto it
18.07.2019 | Potsdam-Institut für Klimafolgenforschung
Adjusting the thermal conductivity of materials is one of the challenges nanoscience is currently facing. Together with colleagues from the Netherlands and Spain, researchers from the University of Basel have shown that the atomic vibrations that determine heat generation in nanowires can be controlled through the arrangement of atoms alone. The scientists will publish the results shortly in the journal Nano Letters.
In the electronics and computer industry, components are becoming ever smaller and more powerful. However, there are problems with the heat generation. It is...
Scientists have visualised the electronic structure in a microelectronic device for the first time, opening up opportunities for finely-tuned high performance electronic devices.
Physicists from the University of Warwick and the University of Washington have developed a technique to measure the energy and momentum of electrons in...
Scientists at the University Würzburg and University Hospital of Würzburg found that megakaryocytes act as “bouncers” and thus modulate bone marrow niche properties and cell migration dynamics. The study was published in July in the Journal “Haematologica”.
Hematopoiesis is the process of forming blood cells, which occurs predominantly in the bone marrow. The bone marrow produces all types of blood cells: red...
For some phenomena in quantum many-body physics several competing theories exist. But which of them describes a quantum phenomenon best? A team of researchers from the Technical University of Munich (TUM) and Harvard University in the United States has now successfully deployed artificial neural networks for image analysis of quantum systems.
Is that a dog or a cat? Such a classification is a prime example of machine learning: artificial neural networks can be trained to analyze images by looking...
An international research group led by scientists from the University of Bayreuth has produced a previously unknown material: Rhenium nitride pernitride. Thanks to combining properties that were previously considered incompatible, it looks set to become highly attractive for technological applications. Indeed, it is a super-hard metallic conductor that can withstand extremely high pressures like a diamond. A process now developed in Bayreuth opens up the possibility of producing rhenium nitride pernitride and other technologically interesting materials in sufficiently large quantity for their properties characterisation. The new findings are presented in "Nature Communications".
The possibility of finding a compound that was metallically conductive, super-hard, and ultra-incompressible was long considered unlikely in science. It was...
24.06.2019 | Event News
29.04.2019 | Event News
17.04.2019 | Event News
19.07.2019 | Physics and Astronomy
19.07.2019 | Physics and Astronomy
19.07.2019 | Earth Sciences